P0275
Cylinder 5 Contribution/Balance FaultP0275 is a generic OBD-II powertrain diagnostic trouble code: Cylinder 5 Contribution/Balance Fault. It is logged by the engine control unit when the fuel/inj monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0275 means
P0275 — Cylinder 5 Contribution/Balance Fault — is set when the powertrain control module (PCM) detects that cylinder 5 is producing measurably less power than the other cylinders. The PCM monitors each cylinder's contribution by tracking crankshaft acceleration during every power stroke; if cylinder 5 consistently under-accelerates the crank, the imbalance threshold is crossed and P0275 is stored. The MIL illuminates and a freeze-frame snapshot is saved.
This code applies to any OBD-II engine that has at least five cylinders — inline-5 engines (Audi/VW 2.5 TFSI, Volvo inline-5, Mercedes OM605), inline-6, V6, V8, V10, and large diesel inline configurations such as the Cummins ISB, Duramax LB7/LLY, and Ford 6.0/6.4 Power Stroke are all affected. On diesel platforms the PCM also monitors injector fuel-quantity balance rates (mm³/stroke), and a rate outside the ±4 mg/stroke window will trigger this code even before a noticeable misfire develops.
The root cause is almost always a fuelling problem on cylinder 5 — a clogged, leaking, or electrically compromised injector being the leading suspect — though low compression from a worn ring, burnt valve, or failed head gasket can produce an identical balance fault. Ignoring the code risks catalyst damage from unburned fuel and, in diesel applications, hydrolocked cylinders if an injector is stuck open.
Common causes
Most-frequently reported root causes when P0275 is logged.
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1
Clogged or stuck-open fuel injector on cylinder 5 delivering incorrect fuel quantity.
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2
Failed or intermittently open injector solenoid winding on cylinder 5.
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3
Corroded, loose, or damaged electrical connector at the cylinder 5 injector.
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4
Chafed or broken wiring in the cylinder 5 injector harness causing high resistance.
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5
Low fuel rail pressure causing lean misfire on the most sensitive cylinder.
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6
Low compression on cylinder 5 from worn piston rings, a burnt valve, or a leaking head gasket.
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7
Faulty crankshaft position sensor producing inaccurate cylinder-timing data.
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8
PCM software fault or corrupted injector calibration data (rare).
Symptoms drivers notice
How to diagnose P0275
A typical diagnostic flow when this code is present.
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1
Connect a professional OBD-II scan tool, record all stored DTCs and freeze-frame data, and note any companion misfire codes (P0305).
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2
On diesel vehicles, read live injector balance-rate data; a cylinder 5 rate outside ±4 mg/stroke confirms a fuelling deviation.
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3
Perform a cylinder cut-out or contribution test using a bidirectional scan tool to isolate whether killing cylinder 5 changes idle quality less than other cylinders.
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4
Inspect the cylinder 5 injector electrical connector and harness for corrosion, pushed-out pins, or chafing; measure injector coil resistance (typical range 0.5–2.0 Ω for port injectors, 0.3–1.0 Ω for GDI/CRDI).
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5
Check fuel rail pressure against specification at idle and under load; low pressure affects the weakest cylinder first.
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6
Perform a compression test on cylinder 5; readings more than 10 % below the other cylinders indicate a mechanical cause.
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7
Replace or clean the cylinder 5 injector only after electrical and mechanical checks clear, and re-verify balance rates after repair.
Related powertrain codes
- P0065 — Air Assisted Injector Control Range/Performance
- P0066 — Air Assisted Injector Control Circuit or Circuit Low
- P0067 — Air Assisted Injector Control Circuit High
- P0087 — Fuel Rail/System Pressure - Too Low
- P0088 — Fuel Rail/System Pressure - Too High
- P0089 — Fuel Pressure Regulator 1 Performance
Frequently asked questions
Can I drive with a P0275 code?
Short distances are usually possible, but continued driving risks catalyst damage from misfired unburned fuel and, on diesel engines, potential hydro-lock if the injector is stuck open. Have the vehicle diagnosed promptly.
P0275 appeared together with P0305 — are they related?
Yes. P0305 is a cylinder 5 misfire code and P0275 is the balance-fault companion. Both point to the same cylinder; diagnose them together, starting with the injector and ignition system before moving to compression testing.
Does P0275 only affect diesel engines?
No. The code is generic OBD-II and applies to petrol and diesel engines alike, including inline-5, V6, V8, and V10 layouts. Diesel platforms (Duramax, Power Stroke, Cummins) simply provide more precise balance-rate data to assist diagnosis.
Will cleaning the injector fix P0275?
Ultrasonic cleaning can restore an injector with a partially blocked filter screen or deposit buildup. However, if the injector coil is open or the spray pattern is mechanically deformed, the injector must be replaced. Always verify with balance-rate data after any service.
Disabling P0275 in software
RaceTune can permanently disable P0275 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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